1. Field of the Invention
The present invention relates to a medium distinguishing method used for a disk drive into which a low-capacity disk and a high-capacity disk can be loaded, the distinguishing method allowing a medium which cannot be distinguished from the low-capacity disk when mounted to be determined to be either a low-capacity disk or a high-capacity disk.
2. Description of the Related Art
Floppy disks (hereinafter called FDs) having a capacity of 1 MB or 2 MB (hereinafter referred to as 1/2 MB) have been generally used as media for recording computer data. As data becomes large due to recent large-capacity application software for personal computers, a high-capacity disk (hereinafter called a first-standard high-capacity medium) having a high capacity of 200 MB, which is far larger than that of a FD, has been developed. It is assumed that a drive for this high-capacity medium can record and reproduce data into and from both of the first-standard high-capacity medium and the conventional 1/2-MB low-capacity disk (FD). The
The first-standard high-capacity medium is accommodated into a hard case and loaded into the drive. This hard case is nearly the same as that for the conventional FD in shape and size. Since, precisely, the hard cases of the first-standard high-capacity medium and the FD differ in shape to allow them to be physically identified, however, when the first-standard high-capacity medium is inserted to the dedicated drive, the drive recognizes the medium immediately and performs recording or reproduction with the use of a head dedicated to the medium. When the FD is inserted, it is expected that the drive recognizes the FD and performs recording or reproduction with the use of a head dedicated to the FD.
In the dedicated drive, the head for the conventional FD and the head for the first-standard high-capacity medium are mounted in a common slider with separate processing circuits being connected to these heads.
Drives have been commercially available already which can record and reproduce data into and from another medium (hereinafter called another-standard high-capacity medium) having a capacity of 120 MB, those drives serving as upper compatible devices with FD drives.
Since this another-standard high-capacity medium is almost the same as the FD in terms of the shapes and the sizes of their hard cases, if the another-standard high-capacity medium is inserted into a drive dedicated to the first-standard high-capacity medium, the drive cannot determine whether the inserted medium is an another-standard high-capacity medium or an FD. The hard case of an FD has a square hole used for enabling or disabling a write operation while the hard case of an another-standard high-capacity medium is solid at the portion corresponding to the square hole. Therefore, when an another-standard high-capacity medium is inserted into a drive dedicated to the first-standard high-capacity medium, the drive recognizes that an FD to which writing is disabled has been inserted.
On the other hand, since tracking servo with the use of optical servo is used for the another-standard high-capacity medium whereas optical servo is not used for the first-standard high-capacity medium, a drive dedicated to the another-standard high-capacity medium can identify the first-standard high-capacity medium by recognizing whether an optical servo pattern exists. Therefore, when a drive dedicated to the first-standard high-capacity medium is provided with an optical servo unit, the another-standard high-capacity medium can be identified. However, providing this optical servo unit increases cost and is unrealistic.
It is also possible that when a medium is inserted into a drive dedicated to the first-standard high-capacity medium, a reproduction operation is immediately performed and if a signal having the format unique to the first-standard high-capacity capacity medium or a signal having the format unique to the FD is reproduced, the medium is recognized as such, or if a signal is not reproduced as either of the above, the medium is determined to be an another-standard high-capacity medium.
In this determination method, however, since a read signal needs to be sent to the host computer and signal processing is required for determination, it takes some time. In addition, when a medium is inserted, since two types of operations are required, one for reproduction operation by rotating the medium at a low speed corresponding to the FD and the other for reproduction operation by rotating the medium at a high speed corresponding to the first-standard high-capacity medium, prompt determination is difficult. Furthermore, since operation-control processing for determination is complicated, the load of a control circuit, including the CPU, increases.
The present invention has been made to solve the above problems. Accordingly, it is an object of the present invention to provide a medium distinguishing method in which a drive easily distinguishes low-capacity disks appropriate for the drive to receive and other media which the drive needs to reject.
The foregoing object is achieved in one aspect of the present invention through the provision of a medium distinguishing method for a disk drive which allows recording and reproduction to be performed for a low-capacity disk and a high-capacity disk, which is provided with identifying means for identifying the low-capacity disk and the high-capacity disk loaded, and which can mount another medium which cannot be distinguished from the low-capacity disk when loaded, wherein, when the loaded medium is not determined to be a high-capacity disk, a difference in the recording condition of the medium is detected by the use of a head to distinguish the low-capacity disk and the another medium.
As described above, a medium distinguishing method according the present invention allows the floppy disk and the another-standard high-capacity medium which cannot be distinguished physically to be distinguished with the use of the medium magnetic characteristics.
In this case, the distinction can be made by the use of a difference in radius range used or a difference in track pitch in data recording zones.
For example, the formatted area of the another-standard high-capacity medium is formed wider than that of the FD in the inside direction and the outside direction.
Therefore, a reproduction output is read by a head and a difference in the used radius range of a data zone or a formatted zone is detected to distinguish both media.
In this case, a reproduction output of the loaded medium is detected by a head provided for the drive to determine a difference in the inside used-radius position or the outside used-radius position.
To determine a difference at an inside position with the above means, the head is first moved to a position more inside than the innermost position of the data zone or the formatted zone, the head is then sequentially moved outside from that position, and a reproduction output of the medium is read.
Since the another-standard high-capacity medium has a data zone or a formatted zone starting from a position more inside than that in the FD, when a reproduction output is obtained by the use of a head at an inside position more inside than the innermost position of the data zone of the FD, the loaded medium is determined to be an another-standard high-capacity medium and it is ejected from the drive.
Even in a case in which a difference is detected at an outside position, when a reproduction output is obtained at a position more outside than the outermost position of the data zone or the formatted zone of the FD, the loaded medium is determined to be an another-standard high-capacity medium and it is ejected from the drive. A difference in track pitch may be used to identify the loaded medium.
A drive for the first-standard high-capacity medium is provided with both heads for a high-capacity disk and a low-capacity disk. Both heads are mounted on a common slider.
When a reproduction operation is performed with the use of the head for a high-capacity disk to identify the loaded medium, a reproduction output of the head can be detected by the use of a tracking-servo-signal detection section provided for a reproduction path for the head. Since the tracking-servo-signal detection section is used, a special circuit for detecting a reproduction output (envelope) is unnecessary.
In this case, when a disk which needs distinction is loaded, the loaded medium is rotated at a high speed such as 3600 rpm and a reproduction output is detected as an envelope to perform the above distinction.
Alternatively, a reproduction operation is performed with the use of the head for a low-capacity disk to identify the loaded medium, and a reproduction output of the head is detected by the use of an envelope detection circuit added to a reproduction path for the head.
In this case, when a disk which needs distinction is loaded, the loaded medium is rotated at a low speed such as 300 rpm and a reproduction output is detected as an envelope.
The foregoing object is achieved in another aspect of the present invention through the provision of a medium distinguishing method for a disk drive which allows recording and reproduction to be performed for a low-capacity disk and a high-capacity disk, which is provided with identifying means for identifying the low-capacity disk and the high-capacity disk loaded, and which can mount another medium which cannot be distinguished from the low-capacity disk when loaded, wherein, when the loaded medium is not determined to be a high-capacity disk, high-frequency determination data is recorded at an area more inside than the data zone and it is determined whether the determination data can be read in a reproduction operation to distinguish the low-capacity disk and the another medium.
As described above, the floppy disk and the another-standard high-capacity medium which cannot be distinguished physically are allowed to be distinguished with the use of the medium magnetic characteristics, especially recording characteristics and reproduction characteristics.
When a floppy disk or an another-standard high-capacity medium is inserted into a drive, determination data is written by a head into an unused area located at the innermost position of the inserted medium and where data is not recorded or reproduced at all, and it is determined whether the reproduction output corresponding to the written determination data is obtained to identify the loaded medium.
In this case, the loaded medium is rotated at the low speed corresponding to the rotation frequency of the low-capacity disk, and the determination data is recorded or reproduced by the use of a head for the high-capacity disk. Alternatively, the loaded medium is rotated at the high speed corresponding to the rotation frequency of the high-capacity disk, and the determination data is recorded or reproduced by the use of a head for the high-capacity disk.
Since the FD, which is a low-capacity medium, has a low coercive force and a thick magnetic layer, remanence is small when magnetic recording is performed with a high-frequency signal. Therefore, even if an attempt is made to record a high-frequency signal for the first-standard high-capacity medium into the FD, recording cannot be performed. Consequently, a reproduction output is very weak when such recording and reproduction are performed. On the other hand, since it is expected that a high-frequency signal is recorded into the another-standard high-capacity medium, after high-frequency determination data is written, its reproduction output is obtained. Therefore, by recording and reproduction of the determination data, a low-capacity disk such as the FD and other media which are not to be handled can be distinguished.